Patent US5475221A successfully refreshed from Google Patents.
US5475221A
Expired / Lapsed
US
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Optical spectrometer using light emitting diode array
Assignee: Brimrose Corp of America
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Filing: 1994-05-11
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Granted: 1995-12-12
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Expires: 2014-05-11
Abstract
Abstract A novel optical device is provided which uses an array of light emitting diodes, controlled by novel multiplexing schemes, to replace conventional broad band light sources in devices such as spectrometers.
Inventors
- 👤 Xiaolu Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:03
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/12; G01J3/1256; G01J3/02; G01J3/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
91 words
A spectrometer comprising: a broad band light source, said source comprising an array of light emitting diodes, the individual diodes of which each emit a narrow wavelength band but the combination of which emit a desired range of wavelengths; switch means for controlling whether an individual diode is on or off at any given time; and multiplexing means for controlling said switch means so as to produce a desired total wavelength range; and a monochromator comprising an acousto-optic tunable filter means optically coupled and responsive to said broad band light source.
Claim 2
Dependent Claim
91 words
A spectrometer comprising: a broad band light source, said source comprising an array of light emitting diodes, the individual diodes of which each emit a narrow wavelength band but the combination of which emit a desired range of wavelengths; switch means for controlling whether an individual diode is on or off at any given time; and multiplexing means for controlling said switch means so as to produce a desired total wavelength range; and a monochromator comprising an acousto-optic tunable filter means optically coupled and responsive to said broad band light source.
Claim 3
Dependent Claim
45 words
A spectrometer as in claim 1 wherein the multiplexing means comprises time domain multiplexing means; means by which each individual LED is turned on/off according to a specific time sequence so that a desired broad wavelength region can be covered within a given time span.
Claim 4
Dependent Claim
35 words
A spectrometer as in claim 1 wherein the multiplexing means comprises frequency domain multiplexing; and further comprising means by which each individual LED is modulated by reference signals with different frequencies through electrical bias currents.
Claim 5
Dependent Claim
23 words
A spectrometer as in claim 3 further comprising discrimination means for discriminating between light originated from different wavelength sub-regions according to modulated frequency.
Claim 6
Dependent Claim
24 words
A spectrometer as in claim 3 further comprising discrimination means for discriminating simultaneously between light originated from different wavelength sub-regions according to modulated frequencies.
Claim 7
Dependent Claim
102 words
A spectrometer comprising: a broad band light source, said source comprising an array of light emitting diodes, the individual diodes of which each emit a narrow wavelength band but the combination of which emit a desired range of wavelength; the optical intensity of the LED array being amplitude modulated by a reference signal through electrical bias current; a monochromator comprising an acousto-optic tunable filter optically coupled and responsive to said broad band light source; a reference signal, and a lock-in amplifier for selectively amplifying a detected signal only if said signal is in proper phase and frequency compared to the reference signal.
Claim 8
Dependent Claim
102 words
A spectrometer comprising: a broad band light source, said source comprising an array of light emitting diodes, the individual diodes of which each emit a narrow wavelength band but the combination of which emit a desired range of wavelength; the optical intensity of the LED array being amplitude modulated by a reference signal through electrical bias current; a monochromator comprising an acousto-optic tunable filter optically coupled and responsive to said broad band light source; a reference signal, and a lock-in amplifier for selectively amplifying a detected signal only if said signal is in proper phase and frequency compared to the reference signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-12-11 | 1999-06-12 | 1999-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-11 | 2003-06-12 | 2003-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-11 | 2007-06-12 | 2007-12-12 | $7700.00 | Window Closed / Lapsed |